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Updated: Aug 25, 2026

Agrobacterium tumefaciens-Mediated Genetic Engineering of Green Microalgae, Chlorella vulgaris
Published on: October 27, 2023
The non-photosynthetic, pathogenic green alga Helicosporidium sp. has retained a modified, functional plastid genome
Aurélien Tartar1, Drion G Boucias
1Department of Entomology and Nematology, University of Florida, Gainesville, FL 32611-0620, USA. dgb@mail.ifas.ufl.edu
Abstract:
A fragment of the Helicosporidium sp. (Chlorophyta: Trebouxiophyceae) plastid genome has been sequenced. The genome architecture was compared to that of both a non-photosynthetic relative (Prototheca wickerhamii) and a photosynthetic relative (Chlorella vulgaris). Comparative genomic analysis indicated that Helicosporidium and Prototheca are closely related genera. The analyses also revealed that the Helicosporidium sp. plastid genome has been rearranged. In particular, two ribosomal protein-encoding genes (rpl19 and rps23) appeared to have been transposed, or lost from the Helicosporidium sp. plastid genome. RT-PCR reactions demonstrated that the retained plastid genes were transcribed, suggesting that, despite rearrangement(s), the Helicosporidium sp. plastid genome has remained functional. The modified plastid genome architecture is a novel apomorphy that indicates that the Helicosporidia are highly derived green algae, more so than Prototheca spp. As such, they represent a promising model to study organellar genome reorganizations in parasitic protists.
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